This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Making decisions in situations where the probabilities of success are either completely unknown (i.e. uncertainty) or known (i.e. risk) is an important part of a person's everyday life and can have significant health consequences. There are individual differences in decision-making that are likely due to a person's biologically based autonomic nervous system reactivity. Genetic variation in components of neurotransmitter systems (e.g. receptors or transporters) is likely to play an important role in autonomic nervous system activation and regulation. Our long-term goal is to facilitate the development of prevention and treatment methods for mental illness and behavioral disorders based on an understanding of the mechanisms that influence the propensity to engage in health-risk behaviors (HRB) via genetic variation in neurotransmitter systems and their subsequent influence on behavior. It is in that context that we are proposing to examine basic mechanisms involved with decision-making. We will test the following hypotheses: a. Measures of autonomic activation are associated with decision-making and with the personality trait Neuroticism. b. Genetic differences on decision-making are mediated by autonomic activation. c. Gender moderates the associations between neurotransmitter genes and decision-making.